Field of the Invention
The present invention relates to a test apparatus for measuring the effect of a head impact on the brain, inside of the skull and connections to the neck. and tests methods employing the test apparatus.
Background
Chronic traumatic encephalopathy (CTE) is a progressive degenerative disease resulting from a head trauma and particularly a history of repetitive head trauma. Military personnel may be exposed to blasts and other head impacts which may lead to development of CTE. Other environments where people may be subjected to head trauma is the health care industry, industrial environments, such as in a factory or construction site, and commercial industries. Athletes participating in contact sports such as football, soccer, rugby and boxing incur repetitive head trauma that has been shown to lead to the development of CTE in some individuals. CTE may result from symptomatic concussions as well as sub-concussive head trauma. Many athletes may experience frequency sub-concussive head trauma during participation in a contact sport and never have a symptomatic concussion. These athletes may still develop CTE however and the effects of these frequent head impacts is a growing concern.
CTE may result from repetitive damage to axons in the brain, such as shearing caused by high acceleration of the brain tissue. High acceleration is caused by rapid head velocity change, such as that caused by an impact to the head. Axons connect neurons in the brain. Damage to the axons can result in immediate effects and/or delayed effects, such as CTE. Brain injury, such as axonal shearing, may create neurochemical and neurometabolic cascade effects. Even mild trauma to the brain can result in neuronal depolarization which leads to neuronal discharge and the release of neurotransmitters and increased extra cellular potassium (K+). This may be followed by an increased glucose demand and metabolism (hyperglycolysis) and a resultant relative ischemia from reduced cerebral blood flow. Axonal injury may also result from an influx of extra cellular calcium that reduces cerebral blood flow through vasoconstriction, and the release of oxygen free radicals. These neurochemical and neurometabolic effects from even mild head trauma, may result in the development of CTE.